It is known in the industry to use ceramic bearing components in both slide bearing applications and roller bearing applications. The bearing components can be, for example, roll bodies or bearing rings of a ceramic roller bearing of a hybrid roller bearing (rings of roller bearing steel) or of a slide bearing. These bearing components can be made of sintered and hot-pressed ceramic, among others, to produce components having good fatigue and abrasion resistance (high wear resistance, low wear rate). Silicon nitride is one such type of material. Hot-pressed (HPSN), hot-isostatically pressed (HIPSN) and directly sintered silicon nitride (SSN) are commonly used. In addition, ceramic bearing components can also be made, for example, from zirconium oxide, aluminum dioxide and silicon carbide.
Published European Application No. 0 366 443 discloses ceramic bearing elements and a process for producing such bearing elements. The bearing elements are formed from a ceramic material which has a content of metallic components in an amount of 3500 ppm or less and which contains several of the elements iron, nickel, chromium and tungsten. In the disclosed process for producing a ceramic roller bearing element, raw ceramic material powder is converted into a slurry form. The slurry is granulated, shaped into the desired form, and sintered. During the process, metallic components are reduced to a residual value of 3500 ppm or less.
Although ceramic bearing components have repeatedly proven themselves because they have a comparatively long service life even under extreme conditions, for example high temperatures or lubricant loss, the use of ceramic bearing components has long been limited mainly to the area of special applications. This is due at least in part to the fact that the production costs of bearing components when using known production processes are distinctly higher than the production costs for comparable bearing components of steel.
It would thus be desirable to develop a process for producing ceramic bearing components which is cost favorable while still capable of meeting the high quality demands which prevail in the domain of bearing engineering.